Changing views on open-angle glaucoma: Definitions and prevalences - The Rotterdam study

PURPOSE. TO create a quantitative basis for diagnostic criteria for open-an gle glaucoma (OAG), to propose an epidemiologic definition for OAG based on these, and to determine the prevalence of OAG in a general white populatio n. METHODS. Of the 7983 subjects 55 years of age or older participating in the population-based Rotterdam Study, 6756 subjects participated in the ophtha lmic part of this study (6281 subjects living independently and 475 in nurs ing homes). The criteria for the diagnosis of OAG were based on ophthalmosc opic and semiautomated Imagenet estimations of the optic disc such as verti cal cup-to-disc ratio (VCDR), minimal width of neural rim, or asymmetry in VCDR between both eyes, and visual field testing with kinetic Goldmann peri metry. AU criteria for the diagnosis of OAG were assessed in a masked way i ndependently of each other. RESULTS. Mean VCDR on ophthalmoscopy was 0.3 and with Imagenet 0.49, and th e 97.5th percentile for both was 0.7. The prevalence of glaucomatous visual field defects was 1.5%. Overall prevalence of definite OAG in the independ ently living subjects was 0.8% (95% confidence interval [CI] 0.6, 1.0; 50 c ases). Prevalence of OAG in men was double that in women (odds ratio 2.1; 9 5% CI 1.2, 3.6). Different commonly used criteria for diagnosis of OAG resu lted in prevalence figures ranging from 0.1% to 1.2%. CONCLUSIONS. The overall prevalence of OAG in the present study was compara ble to most population-based studies. However, prevalence figures differed by a factor of 12 when their criteria for OAG were applied to this populati on. A definition for definite OAG is proposed: a glaucomatous optic neuropa thy in eyes with open angles in the absence of history or signs of secondar y glaucoma characterized by glaucomatous changes based on the 97.5 percenti le for this population together with glaucomatous visual field loss. In the absence of the latter or of a visual field test, it is proposed to speak o f probable OAG based on the 99.5th or possible OAG based on the 97.5th perc entiles of glaucomatous disc changes for a population under study.